diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index d4a3ef4..6247de8 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -9,12 +9,10 @@ jobs:
         emacs_version:
           - '29.3'
     steps:
-    - uses: mamba-org/setup-micromamba@v1
+    - uses: mamba-org/setup-micromamba@v1.9.0
       with:
-        micromamba-version: '1.5.8-0'
+        micromamba-version: '1.5.6-0'
         environment-file: env-${{ matrix.emacs_version }}.yml
-        init-shell: >-
-          bash
         cache-environment: true
         post-cleanup: 'all'
 
@@ -22,6 +20,7 @@ jobs:
       run: docker-compose up -d
 
     - name: Run tests
+      shell: micromamba-shell {0}
       run: |
         export LD_PRELOAD=/usr/lib/libc_malloc_debug.so
         make install